1 /*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
4
5 This program can be distributed under the terms of the GNU GPL.
6 See the file COPYING.
7 */
8
9 #ifndef _FS_FUSE_I_H
10 #define _FS_FUSE_I_H
11
12 #include <linux/fuse.h>
13 #include <linux/fs.h>
14 #include <linux/mount.h>
15 #include <linux/wait.h>
16 #include <linux/list.h>
17 #include <linux/spinlock.h>
18 #include <linux/mm.h>
19 #include <linux/backing-dev.h>
20 #include <linux/mutex.h>
21 #include <linux/rwsem.h>
22 #include <linux/rbtree.h>
23 #include <linux/poll.h>
24
25 /** Max number of pages that can be used in a single read request */
26 #define FUSE_MAX_PAGES_PER_REQ 32
27
28 /** Maximum number of outstanding background requests */
29 #define FUSE_MAX_BACKGROUND 12
30
31 /** Congestion starts at 75% of maximum */
32 #define FUSE_CONGESTION_THRESHOLD (FUSE_MAX_BACKGROUND * 75 / 100)
33
34 /** Bias for fi->writectr, meaning new writepages must not be sent */
35 #define FUSE_NOWRITE INT_MIN
36
37 /** It could be as large as PATH_MAX, but would that have any uses? */
38 #define FUSE_NAME_MAX 1024
39
40 /** Number of dentries for each connection in the control filesystem */
41 #define FUSE_CTL_NUM_DENTRIES 3
42
43 /** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem
44 module will check permissions based on the file mode. Otherwise no
45 permission checking is done in the kernel */
46 #define FUSE_DEFAULT_PERMISSIONS (1 << 0)
47
48 /** If the FUSE_ALLOW_OTHER flag is given, then not only the user
49 doing the mount will be allowed to access the filesystem */
50 #define FUSE_ALLOW_OTHER (1 << 1)
51
52 /** List of active connections */
53 extern struct list_head fuse_conn_list;
54
55 /** Global mutex protecting fuse_conn_list and the control filesystem */
56 extern struct mutex fuse_mutex;
57
58 /** FUSE inode */
59 struct fuse_inode {
60 /** Inode data */
61 struct inode inode;
62
63 /** Unique ID, which identifies the inode between userspace
64 * and kernel */
65 u64 nodeid;
66
67 /** Number of lookups on this inode */
68 u64 nlookup;
69
70 /** The request used for sending the FORGET message */
71 struct fuse_req *forget_req;
72
73 /** Time in jiffies until the file attributes are valid */
74 u64 i_time;
75
76 /** The sticky bit in inode->i_mode may have been removed, so
77 preserve the original mode */
78 mode_t orig_i_mode;
79
80 /** Version of last attribute change */
81 u64 attr_version;
82
83 /** Files usable in writepage. Protected by fc->lock */
84 struct list_head write_files;
85
86 /** Writepages pending on truncate or fsync */
87 struct list_head queued_writes;
88
89 /** Number of sent writes, a negative bias (FUSE_NOWRITE)
90 * means more writes are blocked */
91 int writectr;
92
93 /** Waitq for writepage completion */
94 wait_queue_head_t page_waitq;
95
96 /** List of writepage requestst (pending or sent) */
97 struct list_head writepages;
98 };
99
100 /** FUSE specific file data */
101 struct fuse_file {
102 /** Request reserved for flush and release */
103 struct fuse_req *reserved_req;
104
105 /** Kernel file handle guaranteed to be unique */
106 u64 kh;
107
108 /** File handle used by userspace */
109 u64 fh;
110
111 /** Refcount */
112 atomic_t count;
113
114 /** Entry on inode's write_files list */
115 struct list_head write_entry;
116
117 /** RB node to be linked on fuse_conn->polled_files */
118 struct rb_node polled_node;
119
120 /** Wait queue head for poll */
121 wait_queue_head_t poll_wait;
122 };
123
124 /** One input argument of a request */
125 struct fuse_in_arg {
126 unsigned size;
127 const void *value;
128 };
129
130 /** The request input */
131 struct fuse_in {
132 /** The request header */
133 struct fuse_in_header h;
134
135 /** True if the data for the last argument is in req->pages */
136 unsigned argpages:1;
137
138 /** Number of arguments */
139 unsigned numargs;
140
141 /** Array of arguments */
142 struct fuse_in_arg args[3];
143 };
144
145 /** One output argument of a request */
146 struct fuse_arg {
147 unsigned size;
148 void *value;
149 };
150
151 /** The request output */
152 struct fuse_out {
153 /** Header returned from userspace */
154 struct fuse_out_header h;
155
156 /*
157 * The following bitfields are not changed during the request
158 * processing
159 */
160
161 /** Last argument is variable length (can be shorter than
162 arg->size) */
163 unsigned argvar:1;
164
165 /** Last argument is a list of pages to copy data to */
166 unsigned argpages:1;
167
168 /** Zero partially or not copied pages */
169 unsigned page_zeroing:1;
170
171 /** Number or arguments */
172 unsigned numargs;
173
174 /** Array of arguments */
175 struct fuse_arg args[3];
176 };
177
178 /** The request state */
179 enum fuse_req_state {
180 FUSE_REQ_INIT = 0,
181 FUSE_REQ_PENDING,
182 FUSE_REQ_READING,
183 FUSE_REQ_SENT,
184 FUSE_REQ_WRITING,
185 FUSE_REQ_FINISHED
186 };
187
188 struct fuse_conn;
189
190 /**
191 * A request to the client
192 */
193 struct fuse_req {
194 /** This can be on either pending processing or io lists in
195 fuse_conn */
196 struct list_head list;
197
198 /** Entry on the interrupts list */
199 struct list_head intr_entry;
200
201 /** refcount */
202 atomic_t count;
203
204 /** Unique ID for the interrupt request */
205 u64 intr_unique;
206
207 /*
208 * The following bitfields are either set once before the
209 * request is queued or setting/clearing them is protected by
210 * fuse_conn->lock
211 */
212
213 /** True if the request has reply */
214 unsigned isreply:1;
215
216 /** Force sending of the request even if interrupted */
217 unsigned force:1;
218
219 /** The request was aborted */
220 unsigned aborted:1;
221
222 /** Request is sent in the background */
223 unsigned background:1;
224
225 /** The request has been interrupted */
226 unsigned interrupted:1;
227
228 /** Data is being copied to/from the request */
229 unsigned locked:1;
230
231 /** Request is counted as "waiting" */
232 unsigned waiting:1;
233
234 /** State of the request */
235 enum fuse_req_state state;
236
237 /** The request input */
238 struct fuse_in in;
239
240 /** The request output */
241 struct fuse_out out;
242
243 /** Used to wake up the task waiting for completion of request*/
244 wait_queue_head_t waitq;
245
246 /** Data for asynchronous requests */
247 union {
248 struct fuse_forget_in forget_in;
249 struct {
250 struct fuse_release_in in;
251 struct vfsmount *vfsmount;
252 struct dentry *dentry;
253 } release;
254 struct fuse_init_in init_in;
255 struct fuse_init_out init_out;
256 struct {
257 struct fuse_read_in in;
258 u64 attr_ver;
259 } read;
260 struct {
261 struct fuse_write_in in;
262 struct fuse_write_out out;
263 } write;
264 struct fuse_lk_in lk_in;
265 } misc;
266
267 /** page vector */
268 struct page *pages[FUSE_MAX_PAGES_PER_REQ];
269
270 /** number of pages in vector */
271 unsigned num_pages;
272
273 /** offset of data on first page */
274 unsigned page_offset;
275
276 /** File used in the request (or NULL) */
277 struct fuse_file *ff;
278
279 /** Inode used in the request or NULL */
280 struct inode *inode;
281
282 /** Link on fi->writepages */
283 struct list_head writepages_entry;
284
285 /** Request completion callback */
286 void (*end)(struct fuse_conn *, struct fuse_req *);
287
288 /** Request is stolen from fuse_file->reserved_req */
289 struct file *stolen_file;
290 };
291
292 /**
293 * A Fuse connection.
294 *
295 * This structure is created, when the filesystem is mounted, and is
296 * destroyed, when the client device is closed and the filesystem is
297 * unmounted.
298 */
299 struct fuse_conn {
300 /** Lock protecting accessess to members of this structure */
301 spinlock_t lock;
302
303 /** Mutex protecting against directory alias creation */
304 struct mutex inst_mutex;
305
306 /** Refcount */
307 atomic_t count;
308
309 /** The user id for this mount */
310 uid_t user_id;
311
312 /** The group id for this mount */
313 gid_t group_id;
314
315 /** The fuse mount flags for this mount */
316 unsigned flags;
317
318 /** Maximum read size */
319 unsigned max_read;
320
321 /** Maximum write size */
322 unsigned max_write;
323
324 /** Readers of the connection are waiting on this */
325 wait_queue_head_t waitq;
326
327 /** The list of pending requests */
328 struct list_head pending;
329
330 /** The list of requests being processed */
331 struct list_head processing;
332
333 /** The list of requests under I/O */
334 struct list_head io;
335
336 /** The next unique kernel file handle */
337 u64 khctr;
338
339 /** rbtree of fuse_files waiting for poll events indexed by ph */
340 struct rb_root polled_files;
341
342 /** Number of requests currently in the background */
343 unsigned num_background;
344
345 /** Number of background requests currently queued for userspace */
346 unsigned active_background;
347
348 /** The list of background requests set aside for later queuing */
349 struct list_head bg_queue;
350
351 /** Pending interrupts */
352 struct list_head interrupts;
353
354 /** Flag indicating if connection is blocked. This will be
355 the case before the INIT reply is received, and if there
356 are too many outstading backgrounds requests */
357 int blocked;
358
359 /** waitq for blocked connection */
360 wait_queue_head_t blocked_waitq;
361
362 /** waitq for reserved requests */
363 wait_queue_head_t reserved_req_waitq;
364
365 /** The next unique request id */
366 u64 reqctr;
367
368 /** Connection established, cleared on umount, connection
369 abort and device release */
370 unsigned connected;
371
372 /** Connection failed (version mismatch). Cannot race with
373 setting other bitfields since it is only set once in INIT
374 reply, before any other request, and never cleared */
375 unsigned conn_error:1;
376
377 /** Connection successful. Only set in INIT */
378 unsigned conn_init:1;
379
380 /** Do readpages asynchronously? Only set in INIT */
381 unsigned async_read:1;
382
383 /** Do not send separate SETATTR request before open(O_TRUNC) */
384 unsigned atomic_o_trunc:1;
385
386 /** Filesystem supports NFS exporting. Only set in INIT */
387 unsigned export_support:1;
388
389 /*
390 * The following bitfields are only for optimization purposes
391 * and hence races in setting them will not cause malfunction
392 */
393
394 /** Is fsync not implemented by fs? */
395 unsigned no_fsync:1;
396
397 /** Is fsyncdir not implemented by fs? */
398 unsigned no_fsyncdir:1;
399
400 /** Is flush not implemented by fs? */
401 unsigned no_flush:1;
402
403 /** Is setxattr not implemented by fs? */
404 unsigned no_setxattr:1;
405
406 /** Is getxattr not implemented by fs? */
407 unsigned no_getxattr:1;
408
409 /** Is listxattr not implemented by fs? */
410 unsigned no_listxattr:1;
411
412 /** Is removexattr not implemented by fs? */
413 unsigned no_removexattr:1;
414
415 /** Are file locking primitives not implemented by fs? */
416 unsigned no_lock:1;
417
418 /** Is access not implemented by fs? */
419 unsigned no_access:1;
420
421 /** Is create not implemented by fs? */
422 unsigned no_create:1;
423
424 /** Is interrupt not implemented by fs? */
425 unsigned no_interrupt:1;
426
427 /** Is bmap not implemented by fs? */
428 unsigned no_bmap:1;
429
430 /** Is poll not implemented by fs? */
431 unsigned no_poll:1;
432
433 /** Do multi-page cached writes */
434 unsigned big_writes:1;
435
436 /** The number of requests waiting for completion */
437 atomic_t num_waiting;
438
439 /** Negotiated minor version */
440 unsigned minor;
441
442 /** Backing dev info */
443 struct backing_dev_info bdi;
444
445 /** Entry on the fuse_conn_list */
446 struct list_head entry;
447
448 /** Device ID from super block */
449 dev_t dev;
450
451 /** Dentries in the control filesystem */
452 struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
453
454 /** number of dentries used in the above array */
455 int ctl_ndents;
456
457 /** O_ASYNC requests */
458 struct fasync_struct *fasync;
459
460 /** Key for lock owner ID scrambling */
461 u32 scramble_key[4];
462
463 /** Reserved request for the DESTROY message */
464 struct fuse_req *destroy_req;
465
466 /** Version counter for attribute changes */
467 u64 attr_version;
468
469 /** Called on final put */
470 void (*release)(struct fuse_conn *);
471 };
472
get_fuse_conn_super(struct super_block * sb)473 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
474 {
475 return sb->s_fs_info;
476 }
477
get_fuse_conn(struct inode * inode)478 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
479 {
480 return get_fuse_conn_super(inode->i_sb);
481 }
482
get_fuse_inode(struct inode * inode)483 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
484 {
485 return container_of(inode, struct fuse_inode, inode);
486 }
487
get_node_id(struct inode * inode)488 static inline u64 get_node_id(struct inode *inode)
489 {
490 return get_fuse_inode(inode)->nodeid;
491 }
492
493 /** Device operations */
494 extern const struct file_operations fuse_dev_operations;
495
496 extern struct dentry_operations fuse_dentry_operations;
497
498 /**
499 * Get a filled in inode
500 */
501 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
502 int generation, struct fuse_attr *attr,
503 u64 attr_valid, u64 attr_version);
504
505 int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name,
506 struct fuse_entry_out *outarg, struct inode **inode);
507
508 /**
509 * Send FORGET command
510 */
511 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
512 u64 nodeid, u64 nlookup);
513
514 /**
515 * Initialize READ or READDIR request
516 */
517 void fuse_read_fill(struct fuse_req *req, struct file *file,
518 struct inode *inode, loff_t pos, size_t count, int opcode);
519
520 /**
521 * Send OPEN or OPENDIR request
522 */
523 int fuse_open_common(struct inode *inode, struct file *file, int isdir);
524
525 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc);
526 void fuse_file_free(struct fuse_file *ff);
527 void fuse_finish_open(struct inode *inode, struct file *file,
528 struct fuse_file *ff, struct fuse_open_out *outarg);
529
530 /** Fill in ff->reserved_req with a RELEASE request */
531 void fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags, int opcode);
532
533 /**
534 * Send RELEASE or RELEASEDIR request
535 */
536 int fuse_release_common(struct inode *inode, struct file *file, int isdir);
537
538 /**
539 * Send FSYNC or FSYNCDIR request
540 */
541 int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
542 int isdir);
543
544 /**
545 * Notify poll wakeup
546 */
547 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
548 struct fuse_notify_poll_wakeup_out *outarg);
549
550 /**
551 * Initialize file operations on a regular file
552 */
553 void fuse_init_file_inode(struct inode *inode);
554
555 /**
556 * Initialize inode operations on regular files and special files
557 */
558 void fuse_init_common(struct inode *inode);
559
560 /**
561 * Initialize inode and file operations on a directory
562 */
563 void fuse_init_dir(struct inode *inode);
564
565 /**
566 * Initialize inode operations on a symlink
567 */
568 void fuse_init_symlink(struct inode *inode);
569
570 /**
571 * Change attributes of an inode
572 */
573 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
574 u64 attr_valid, u64 attr_version);
575
576 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
577 u64 attr_valid);
578
579 void fuse_truncate(struct address_space *mapping, loff_t offset);
580
581 /**
582 * Initialize the client device
583 */
584 int fuse_dev_init(void);
585
586 /**
587 * Cleanup the client device
588 */
589 void fuse_dev_cleanup(void);
590
591 int fuse_ctl_init(void);
592 void fuse_ctl_cleanup(void);
593
594 /**
595 * Allocate a request
596 */
597 struct fuse_req *fuse_request_alloc(void);
598
599 struct fuse_req *fuse_request_alloc_nofs(void);
600
601 /**
602 * Free a request
603 */
604 void fuse_request_free(struct fuse_req *req);
605
606 /**
607 * Get a request, may fail with -ENOMEM
608 */
609 struct fuse_req *fuse_get_req(struct fuse_conn *fc);
610
611 /**
612 * Gets a requests for a file operation, always succeeds
613 */
614 struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file);
615
616 /**
617 * Decrement reference count of a request. If count goes to zero free
618 * the request.
619 */
620 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
621
622 /**
623 * Send a request (synchronous)
624 */
625 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req);
626
627 /**
628 * Send a request with no reply
629 */
630 void fuse_request_send_noreply(struct fuse_conn *fc, struct fuse_req *req);
631
632 /**
633 * Send a request in the background
634 */
635 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req);
636
637 void fuse_request_send_background_locked(struct fuse_conn *fc,
638 struct fuse_req *req);
639
640 /* Abort all requests */
641 void fuse_abort_conn(struct fuse_conn *fc);
642
643 /**
644 * Invalidate inode attributes
645 */
646 void fuse_invalidate_attr(struct inode *inode);
647
648 void fuse_invalidate_entry_cache(struct dentry *entry);
649
650 /**
651 * Acquire reference to fuse_conn
652 */
653 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
654
655 /**
656 * Initialize fuse_conn
657 */
658 int fuse_conn_init(struct fuse_conn *fc, struct super_block *sb);
659
660 /**
661 * Release reference to fuse_conn
662 */
663 void fuse_conn_put(struct fuse_conn *fc);
664
665 /**
666 * Add connection to control filesystem
667 */
668 int fuse_ctl_add_conn(struct fuse_conn *fc);
669
670 /**
671 * Remove connection from control filesystem
672 */
673 void fuse_ctl_remove_conn(struct fuse_conn *fc);
674
675 /**
676 * Is file type valid?
677 */
678 int fuse_valid_type(int m);
679
680 /**
681 * Is task allowed to perform filesystem operation?
682 */
683 int fuse_allow_task(struct fuse_conn *fc, struct task_struct *task);
684
685 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
686
687 int fuse_update_attributes(struct inode *inode, struct kstat *stat,
688 struct file *file, bool *refreshed);
689
690 void fuse_flush_writepages(struct inode *inode);
691
692 void fuse_set_nowrite(struct inode *inode);
693 void fuse_release_nowrite(struct inode *inode);
694
695 u64 fuse_get_attr_version(struct fuse_conn *fc);
696
697 #endif /* _FS_FUSE_I_H */
698